Summary

1. AN ARRAY’S LENGTH SHOULD BE CACHED TO SAVE GAS IN FOR-LOOPS
   Reading array length at each iteration of the loop takes 6 gas (3 for mload and 3 to place memory_offset) in the stack.
   Caching the array length in the stack saves around 3 gas per iteration.

2. ++i costs less than i++
   ++i costs less gas compared to i++ for unsigned integer, as pre-increment is cheaper (about 5 gas per iteration) i++ increments i and returns the initial value of i .

Impact

More Gas will be used otherwise. for chains like ETH, it can be upto 1$ worth of GAS

Tools Used

Manual Review

Recommendations

1. Caching the array length in the stack.

2. use ++i instead of i++